decelerate

1 of 2

verb

de·​cel·​er·​ate (ˌ)dē-ˈse-lə-ˌrāt 

decelerated; decelerating

transitive verb

1

: to reduce the speed of : slow down

decelerate a car

2

: to decrease the rate of progress of

decelerate growth

decelerate soil erosion

intransitive verb

: to move at decreasing speed

deceleration

(ˌ)dē-ˌse-lə-ˈrā-shən 

noun

decelerator

(ˌ)dē-ˈse-lə-rā-tər 

noun

deceleration

2 of 2

noun

de·​cel·​er·​a·​tion (ˌ)dē-ˌse-lə-ˈrā-shən 

plural -s

1

: the act or process of decelerating

deceleration of a truck by braking

deceleration of an aging process

2

: the rate of decrease in velocity

aeromedical research has shown that people can withstand high decelerations

Synonyms of decelerate

Verb

• slow
• brake

Examples of decelerate in a Sentence

Verb

she decelerated the car as we entered the school zone

Recent Examples on the Web

Verb

Apple also said services growth would decelerate in the September quarter. — Bloomberg, Mercury News, 31 July 2026

Hitting the brakes Altman isn’t the only one talking about decelerating AI. — Beatrice Nolan, Fortune, 30 July 2026

Sorge said that this class of space debris decelerates quicker, and also once on the surface the pieces are also more recognizable than broken up chunks of metal. — Leonard David, Space.com, 22 July 2026

That fueled fears that on a per-user basis, Netflix’s engagement is decelerating, indicating headwinds for subscription and ad revenue growth. — Todd Spangler, Variety, 17 July 2026

Word History

Etymology

Verb

de- + accelerate

First Known Use

Verb

1899, in the meaning defined at transitive sense 1

Rhymes for decelerate

• abbreviate
• accelerate
• accommodate
• accumulate
• acuminate
• adjudicate
• adulterate
• affiliate
• agglomerate
• agglutinate
• alleviate
• amalgamate

Kids Definition

decelerate

verb

de·​cel·​er·​ate (ˈ)dē-ˈsel-ə-ˌrāt 

decelerated; decelerating

: to move or cause to move at decreasing speed : slow down

deceleration

(ˌ)dē-ˌsel-ə-ˈrā-shən 

noun

decelerator

(ˈ)dē-ˈsel-ə-ˌrāt-ər 

noun

Medical Definition

decelerate

verb

de·​cel·​er·​ate (ˈ)dē-ˈsel-ə-ˌrāt 

decelerated; decelerating

transitive verb

: to reduce the speed of : slow down

intransitive verb

: to move at decreasing speed

deceleration

(ˌ)dē-ˌsel-ə-ˈrā-shən 

noun